Dental zirconia can no longer be considered un-bondable to tooth tissue. In literature, an increasing number of papers indeed report on the bonding effectiveness of different luting techniques to zirconia. We aimed to disclose general trends in bonding to zirconia by systematically collecting zirconia bond-strength data. A search in PubMed and EMBASE revealed 1,371 bond-strength tests reported on in 144 papers. A macro-shear bond-strength protocol was most frequently used; it revealed significantly lower bond strengths and was less discriminative than the other test methods. Regarding luting technique, the combination of mechanical and chemical pre-treatment appeared particularly crucial to obtain durable bonding to zirconia ceramics. The cement choice was not revealed as a determining factor after aging conditions, as long as composite cement was used. Regarding test protocol, a tensile test appeared more discriminative, particularly when combined with ‘water storage’ aging.
The purpose of this study was to evaluate the fabrication of a complete denture using a CAD/CAM system. Cone beam CT was used to measure the complete denture and the artificial teeth. After a 3D complete denture image was structured using 3D CAD software, we factored out the artificial teeth and obtained a 3D denture base image. A machining center cut an acrylic resin block, and fabricated an acrylic complete denture base. The artificial teeth were bonded to the cut denture base using resin cement. A 3D digitizer digitized the fabricated acrylic denture. We measured the deviations between the master 3D complete denture image and the 3D data of the fabricated acrylic denture. The average deviations from the master 3D image were 0.50 mm for the occlusal surface. This present study indicates that it is possible to fabricate a complete denture using a CAD/CAM system.
A new trial method for complete dentures using rapid prototyping (RP) was compared with the conventional method. Wax dentures were fabricated for 10 edentulous patients. Cone-beam CT was used to scan the wax dentures. Using 3D computer-aided design software, seven 3D denture images with different artificial teeth arrangements were made and seven trial dentures per patient were fabricated accordingly. Two prosthodontists performed a denture try-in for one patient using both conventional and RP methods. The prosthodontists and patients rated satisfaction for both methods using a visual analogue scale. Satisfaction ratings with both conventional and RP methods were compared using the Wilcoxon signed-rank test. Regarding prosthodontist’s ratings, esthetics and stability were rated significantly higher with the conventional method than with the RP method, whereas chair time was rated significantly longer with the RP method than with the conventional method. Although further improvements are needed, the trial method applying RP seems promising.